From 54657e3db73cad36112c1a6e72d440f98eccba05 Mon Sep 17 00:00:00 2001
From: Eli Friedman <efriedma@codeaurora.org>
Date: Thu, 3 Aug 2017 22:27:36 +0000
Subject: [PATCH] [coverage] Special-case calls to noreturn functions.
The code after a noreturn call doesn't execute.
The pattern in the testcase is pretty common in LLVM (a switch with
a default case that calls llvm_unreachable).
Differential Revision: https://reviews.llvm.org/D36250
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@309995 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/CodeGen/CoverageMappingGen.cpp | 12 ++++++++++++
test/CoverageMapping/switch.cpp | 13 +++++++++++++
2 files changed, 25 insertions(+)
diff --git a/lib/CodeGen/CoverageMappingGen.cpp b/lib/CodeGen/CoverageMappingGen.cpp
index 1484ec78b88..28aabd0f071 100644
--- a/lib/CodeGen/CoverageMappingGen.cpp
+++ b/lib/CodeGen/CoverageMappingGen.cpp
@@ -716,6 +716,18 @@ struct CounterCoverageMappingBuilder
terminateRegion(S);
}
+ void VisitCallExpr(const CallExpr *E) {
+ extendRegion(E);
+ for (const Stmt *Child : E->children())
+ this->Visit(Child);
+
+ // Terminate the region when we hit a noreturn function.
+ // (This is helpful dealing with switch statements.)
+ QualType CalleeType = E->getCallee()->getType();
+ if (getFunctionExtInfo(*CalleeType).getNoReturn())
+ terminateRegion(E);
+ }
+
void VisitWhileStmt(const WhileStmt *S) {
extendRegion(S);
diff --git a/test/CoverageMapping/switch.cpp b/test/CoverageMapping/switch.cpp
index 17aa53bb486..52f22e8eda1 100644
--- a/test/CoverageMapping/switch.cpp
+++ b/test/CoverageMapping/switch.cpp
@@ -97,3 +97,16 @@ int fallthrough(int i) { // CHECK-NEXT: File 0, [[@LINE]]:24 -> [[@LINE+12]]:2 =
break;
}
}
+
+void abort(void) __attribute((noreturn));
+ // CHECK: noret
+int noret(int x) { // CHECK-NEXT: File 0, [[@LINE]]:18 -> [[@LINE+9]]:2
+ switch (x) {
+ default: // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:12
+ abort();
+ case 1: // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:13
+ return 5;
+ case 2: // CHECK-NEXT: File 0, [[@LINE]]:3 -> [[@LINE+1]]:14
+ return 10;
+ }
+}
--
GitLab